SUPERB TYRANNOSAURUS SKELETON. The T. bataar was marginally smaller than the T. rex, at 30-40 feet in length, but equipped with the same powerful jaws, monstrous teeth, powerful hind legs, and voracious appetite for prey. Like the T. rex, it also had remarkably short forelimbs, the shortest in relation to body-size of all dinosaurs. It ruled the food chain of the ancient floodplains that are today's Gobi Desert, thinking nothing of taking down the giant Titanosaurs with which it shared the ecosystem. Estimate: $950,000 - $1,500,000.

MATING INSECTS IN AMBER. Only in the fossilized tree resin, Amber, is prehistoric life preserved entirely unchanged for millions of years. The oozing resin would have crept down the ancient pines, occasionally engulfing floral debris, and yet more occasionally, unfortunate little insects. Rarer still, however, is the preservation of life in action as here: a pair of small flying Gnats were doing what came naturally when they were caught in the sticky ooze, trapped forever in a golden prison in flagrante delicto. Estimate: $700 - $1,000.

RARE DODO BIRD SKELETON CAST . The Dodo is one of the most emblematic and immediately recognizable creatures in the world, from its fat round body, to the distinctively bulbous, hooked beak. It even has its own catchphrase: dead as a Dodo. For it is the most famously extinct species of modern times. A flightless bird (for lack of predators, and plenty of food) was found only on the island of Mauritius, in the Indian Ocean, first recorded by Dutch sailors in 1598. Less than 100 years later, it was extinct. This was due partly to the fact that, having evolved on an island free of predators, it had no fear of the humans who hunted it, nor of the animals the sailors brought with them, such as dogs, pigs and crab-eating Macaques. Estimate: $3,500 - $4,500.

ELEPHANT BIRD EGG. This incredible egg is from the largest bird ever to have lived, the 10-foot tall Aepyornis of Madagascar. Known as the Great Elephant Bird, it was perhaps unsurprisingly a ratite (flightless bird) like the Moa, the Rhea or the Ostrich, lacking the keel to its breastbone that would provide sufficient leverage to operate its wings in flight. Believed to have weighed almost 900 lb (400 kg), it was a native of Madagascar that survived at least until the late seventeenth century: the French governor of the island at that time wrote of a reclusive giant bird that laid its eggs in hidden places. Indeed, human desire for these eggs may have been the cause of its extinction, as shell fragments have been found amongst remains of human-made fires, suggesting that they were a substantial food source. Estimate: $35,000 - $50,000.

GIANT SABER-TOOTHED TIGER SKULL CAST. The epitome of North American fossils, the Smilodon is the Official State Fossil of California and one of the most sought-after of all prehistoric relics. Unfortunately, most collectors will rarely even get the chance to acquire one, never mind be able to afford those rare specimens that come on the market. The next best thing, however, is a museum-quality cast such as the present example. The great appeal of these Ice Age predators is of course their amazing teeth. Estimate: $800 - $1,200.

FANTASTICAL ANKYLOSAURID SKULL. The Mongolian name of this bizarre-looking dinosaur seems like a witticism, for Saichania in Mongolian means "beautiful one"; it was in fact coined for the beautiful condition of the first bones found of this late dinosaur species. Presented here is a superb, complete skull with an immediately dramatic and unusual appearance. Estimate: $60,000 - $80,000

FINE "BIRD-DINOSAUR" SKELETON. The Troodontidae were small to medium-sized Theropod Raptors that flourished at the end of the dinosaurs' reign on Earth, prior to the K/T extinction event of 65 million years ago. They were closely related to the Dromaeosauridae family (meaning "running lizard") and were equipped with long slender legs, and frequently a covering of feathers. As this fine and virtually complete skeleton shows, the Troodontids were relatively small, and certainly equipped to run fast, with very long, slender legs, and large, retractable, sickle-shaped claws on the second toe, which would have been raised whilst running. Estimate: $45,000 - $60,000.

FINE "DUCK-BILLED" DINOSAUR SKULL. The Edmontosaurus was one of the duck-billed Hadrosauridae that flourished just prior to the final extinction of the dinosaurs, 65 million years ago. A contemporary of the Triceratops and the T. rex, they ranged widely across North America, but the distribution of their fossils suggests that they preferred a coastal plain habitat. One of the largest of the Hadrosaurs, Edmontosaurus could grow to over 40 feet in length. Estimate: $35,000 - $45,000.

FINE AMERICAN MOSASAUR SKULL. Undisputed Emperors of the high Cretaceous seas, the Mosasauridae were a family of serpentine marine reptiles, apex predators, and scourge of the many and varied ocean-dwelling creatures with which they shared the ancient waters. With a heavy, barrel-shaped body and long propulsive tail, it outlasted all rivals. The family was named for the river Meuse, near Maastricht in the Netherlands, where remains of this astonishing creature were first discovered in the late eighteenth century. Estimate: $30,000 - $40,000.

LARGE MEGA-SHARK JAW WITH FOSSIL TEETH. This immensely impressive reconstructed jaw of the fearsome Miocene Megalodon, is set with 138 painstakingly recovered teeth, carefully selected for size and quality. These teeth are generally all that remain to us of this mighty fish, which ruled the waters across the globe from approximately 28 to 1.5 million years ago; like other sharks, its skeleton was composed of cartilage, which rarely if ever survives in the fossil record. Even the teeth can be very difficult to recover: major localities are in the turbulent, zero-visibility waters off the Carolina estuaries, retrieved by dedicated, life-risking scuba divers. Estimate: $65,000 - $80,000.